Population Density and Spatial Distribution Pattern of Hypera postica (Coleoptera: Curculionidae) in Ardabil, Iran

  • Mona MORADI-VAJARGAH University of Mohaghegh Ardabili, Faculty of Agriculture, Department of Plant Protection, Daneshgah Street, P.O.Box 179, Ardabil
  • Ali GOLIZADEH University of Mohaghegh Ardabili, Faculty of Agriculture, Department of Plant Protection, Daneshgah Street, P.O.Box 179, Ardabil
  • Hooshang RAFIEE-DASTJERDI University of Mohaghegh Ardabili, Faculty of Agriculture, Department of Plant Protection, Daneshgah Street, P.O.Box 179, Ardabil
  • Myron P. ZALUCKI The University of Queensland, School of Biological Sciences, St. Lucia, Queensland 4072
  • Mehdi HASSANPOUR University of Mohaghegh Ardabili, Faculty of Agriculture, Department of Plant Protection, Daneshgah Street, P.O.Box 179, Ardabil
  • Bahram NASERI University of Mohaghegh Ardabili, Faculty of Agriculture, Department of Plant Protection, Daneshgah Street, P.O.Box 179, Ardabil

Abstract

The alfalfa weevil, Hypera postica (Gyllenhal), feeds almost exclusively on alfalfa, Medicago sativa L. in most region of the world where forage crop is grown. It has been investigated the population density and spatial distribution of alfalfa weevil on alfalfa in Ardabil during 2010. Using a 0.25 m2 quadrate sample unit a reliable sample size was 65, with maximum relative variation of 15%. The relative variation (RV) of the primary sampling data was 13.6. The highest population density of the alfalfa weevil was recorded on 17th April. To estimate the spatial distribution pattern of this pest, data were analyzed through index of dispersion, Lloyd’s mean crowding, Morisita’s index and two regression models (Taylor’s Power Law and Iwao’s Patchiness Regression). Taylor’s model showed an aggregated distribution pattern for all life stages. Iwao’s patchiness regression indicated that larvae, adult and total life cycle had aggregated spatial distribution (tc < tt), while pupae of alfalfa weevil exhibited a random pattern. The index of dispersion and Lloyd’s mean crowding methods indicated an aggregated distribution for this insect. Spatial distribution parameters of this species are used to outline a sampling program as well as to estimate population density of H. postica development stages. Optimum sample sizes for estimates of larval density, at three levels of precision, are presented.

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Published
2011-11-21
How to Cite
MORADI-VAJARGAH, M., GOLIZADEH, A., RAFIEE-DASTJERDI, H., ZALUCKI, M. P., HASSANPOUR, M., & NASERI, B. (2011). Population Density and Spatial Distribution Pattern of Hypera postica (Coleoptera: Curculionidae) in Ardabil, Iran. Notulae Botanicae Horti Agrobotanici Cluj-Napoca, 39(2), 42-48. https://doi.org/10.15835/nbha3926381
Section
Research Articles